Steam generator



Jan. 14, 1930.

c'. H. DAvY STEAM GENERATOR Filed March 9, 1927 V2 Sheets-Sheet 2.

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Patented Jan. 14, 1930 UNITED STATES PATENT`- OFFICE CHRISTOPHER H.DAVY, OF BECKENHAM, ENGLAND, ASSIG-NOR TO THE BABCOCK & 'WILCOX COMPANY,OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY STEAM GENERATORApplication led March 9, 1927, Serial No. 173,912, and in Great BritainJune 17, 1926.

This invention relates to a steam boiler that is made in sections, andwill be understood from the description in connection with theaccompanying drawings, in which Fig. 1 is a vertical section through anillustrative embodiment of the invention; Fig. 2 is a section along theline 2-2 of Fig. 1, and Fig. 3 is a vertical section through amodification.

The steam generator or boiler comprises a furnace having two side wallsand a front wall enclosed at the top and formed with an `ash outlet atthe bottom. The rear wall of the furnace has rows of steeply inclinedtubes extending thereacross. The side walls of the furnace are eachformed by a row of tubes on which brick work or tile is superposed insuch a manner that the tubes are complete ly covered by a thin layer ofbrick work or tile. The side wall tubes are expanded into headers whichconnect with a drum or drums of the boiler.

For the purpose of preheating the water that is fed to the tubes at therear of the furnace, which tubes are subjected to radiation7 and inorder to equalize the amount of work done throughout the water tube bankand also for the purpose of eliminating scaling of the rear or radiantheat tubes, the 'heating surface is extended over the lower part of thefurnace, the water from the lower drum being preheated in its passageacross the furnace and back tol the first row of radiant tubes. Thetubes at the rear of the furnace may be divided into two banks, the bankof tubes near the furnace proper being supplied with water that ispreheated in its passage through the lower furnace tubes and connectionsto the steam and water drums are provided so that there will Abe anon-restricted circulation of Water through these tubes. The other bankof tubes at the rear of the furnace may be supplied with'water byconnections entirely separate from those supplying the first bank.

In the drawings reference character 5 indicates the front Wall and 6 theside walls of the furnace, and 7 indicatesair passages that may be usedfor cooling purposes. The upper portion or top 8 of the furnace is pro-50 vided with fuel burners 9 in the well known manner, so that theflames are directed as indicated by the arrows. The side walls 6 arebuilt up around the row of tubes 10, so as to enclose the same withalayer of brick or tile. Each row of tubes 10 is connected to a lowerheader 11 and an upper header 12, and these headers are connected bytubes 13 and 14 to the lower drum 15 and the upper drum 1G of theboiler, respectively. Rows of vertically disposed tubes 17 connectthedrums 15 and 16. Rows of banks of steeply inclined tubes 20 at the rearof the furnace are connected at their lower and upper ends to theheaders 21 and 22, that are connected by the connections or nipples 23and 24, respectively, to the drums 15 and 16. One or more tubes 25connect the lower drum 15 to the horizontal header 26, that may beprovided with a valved drain pipe, extending along one side of the lowerpart of the furnace. A row of tubos 27 extends from theheader 26 to thehorizontal header 28 along the other side of the furnace, and a row ofslag screen tubes 29 extends from the header 28 across the lower portionof the furnace to the headers 21.

A pipe 32 extends from the steam space of the drum 16 to the superheater33 that is located bet-Ween the banks 17 and 20 of tubes and a pipe 34leads from the superheater to the steam main.

An economizer 35 is located at the rear of the bank of tubes 17. Thiseconomizer comprises tubes that are connected to lower` and upperheaders 36 and'37. A feed water pipe 38=leads to a lower header 36 and avalved pipe 39 leads from the upper header 37 to lthe Cil steam andwater drum 16. Baflies 40, 41, 42

and 43 are providedas indicated to direct the passage of the hotproducts of combustion across the tubes. It will be Yobvious from thedescription that there is a localcirculation of water through the sidewall tubes and an independent local circulation of water through thebank of tubes 20. Tn the modification shown in Fig. 3 parts similar tothose already described in connection with Figs. 1 and 2 are designatedvby the' same reference characters with'p'rimes, andl it is not thoughtnecessary to describe them agaln.

In this modification, a second bank of tubes 45 is provided at .the rearof the furnace behind the bank of tubes 20 and are connected to lowerheaders 46 and upper headers 47, which are in turn connected to thedrums 15 and 16 by means of the nipples 48 and 49, respectively. Thecirculation of water through this bank of tubes is entirely independentof the circulation of the water through the bank 20 or the banks 10along the side walls of the furnace.

In both forms shown the connections exemplified by the nipples 23 and 24extend forwardly from the two drums. Some of first mentioned bank oftubes.

CHRISTOPHER H. DAVY.

these connections terminate in the headers 21 and 22, and others in theheaders 11 and 12. In turn, 'some of the headers 21 in effect extendforwardly in the form of the slag screen tubes 29 which are connected attheir forward end to the drum 15. In e'ach case the headers, connectionsand tubes referred to are in line with each other, and in the embodimentof Figs. 1 and 2 there is an actual physical connection between thesedifferent elements, whereby the flow may take place walls,

therethrough.

I claim:

1. In combination, a furnace havng side walls, vertically extendingtubes in said side a bank of vertically extending tubes disposed at therear of said furnace, horizontal upper and lower drums disposedrearwardly of said bank and connected by a second bank of tubes,connections extending forwardly from each of said upper and lower drums,headers for said first mentioned bank of tubes and for said wall tubes,said headers forming extensions of some of'said connections, and slagscreen tubes extending across the bottom of the furnace and formingextensions of some of the headers at the lower end of said firstmentioned bank.

2. In combination, a furnace having side walls, vertically extendingtubes in said side Walls, a bank of vertically extendingtubes disposedat the rear of said furnace, horizontal upper and lower drums disposedrearwardly of said bank and connected by a secr.

ond bank of tubes, connections extending forwardly from each of saidupper and lower drums, headers for said first mentioned bank of tubesand for said wall tubes, said headers forming extensions of some `ofsaid connections, slag screen tubes extending across the bottom of thefurnace and forming extensions

